I made a Expandable String Value, ForcePSTPath, under HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\, and set the value to D:\tmp\outlook. However, the outlook file still in C: drive, not in D drive.

Did you perform the following step (which was right above the Conclusion paragraph)

Now, move all of the contents of your Outlook data folder you opened above to the new folder you specified, and then reopen Outlook. Everything should work as before, except now your Data files are stored where you want them to be stored!

You have to physically perform the copy or move function. Changing the registry key alone is not sufficient.

To move files safely , make sure that Outlook is closed.
then Go to Mail in Control panel (This applied to Window 7 , you should find it also in Windows 8 also ), and from there you can add or remove Outlook files.
Don't forget that after you move an Outlook file , you have to change the path for it in the active email configured on Outlook. (Just click on Emails in the first Tab in your first attached picture) to do this.
Once your changes are done , you can start Outlook.